This invention relates to a camshaft bearing arrangement for an overhead camshaft engine and more particularly to an improved assembly arrangement for the camshaft and other associated components of the engine.
The advantages of overhead camshafts and multiple valve engines for achieving high performance are well acknowledged. In spite of the acknowledged advantages, certain practical aspects have limited the use of overhead camshaft, multiple valve engines for large production volumes. One of the main difficulties in such applications is the positioning of the various components in such a manner as to provide a compact assembly and nevertheless one which can be conveniently manufactured, assembled and serviced. For example, it is desirable to position the camshafts in such a way that they do not substantially increase the width of the cylinder head assembly. However, this gives rise to certain difficulties in connection with the journaling for the camshafts and maintaining adequate clearance and accessibility for the fasteners that secure the cylinder head to the cylinder block. Recently, it has also been proposed to provide more than two intake valves for each cylinder of the engine and the use of three or more intake valves gives rise to additional problems in connection with the camshaft mounting arrangement. It is desirable if the valves can be displaced in such a way so as to operated by a single camshaft. However, if this is done, the intake camshaft may be spaced at a different distance from the center line of the engine than the exhaust camshaft and this can give rise to certain additional difficulties in locating the various fasteners for the engine.
It is, therefore, a principal object of this invention to provide an improved camshaft bearing arrangement for overhead cam engines.
It is a yet further object of this invention to provide an improved camshaft bearing construction for an engine wherein the fasteners for the various components are conveniently located and yet do not interfere with each other.